Regulation of coin metal substituents and cooperativity on the strength and nature of tetrel bonds

Abstract

Ab initio calculations have been performed for the tetrel-bonded dyad MCN⋯TF4 (M = Cu, Ag, and Au; T = C, Si, Ge, and Sn). A coin metal substituent greatly strengthens the tetrel bond, depending on the nature of the coin metal and tetrel atoms. The Ag substituent has the largest enhancing effect with the interaction energy approaching -16 kcal mol-1. The strength of the tetrel bond in MCN⋯TF4 can be further regulated by the cooperative effect with a π⋯metal interaction. It is strengthened in C2H4⋯MCN⋯TF4 but is weakened in C2(CN)4⋯MCN⋯TF4. The interaction energy of the tetrel bond amounts to about -16 kcal mol-1 in C2H4⋯CuCN⋯SiF4, becoming a strong interaction. The nature of the tetrel bond is changed due to the metal substituents and cooperativity.